Fig. 1

Study design of computed tomography screening for normal lung function + lung cancer group, PRISm + lung cancer group and COPD + lung cancer group in Nanjing. GLOD: Global Initiative on Chronic Obstructive Pulmonary Disease; COPD: Chronic Obstructive Pulmonary Disease; PRISm: Preserved Ratio-Impaired Spirometry; HRCT: High Resolution Computed Tomography